Merge branch 'gb/gitweb-remote-heads'

Merge branch 'gb/gitweb-remote-heads'

* gb/gitweb-remote-heads:
  git instaweb: enable remote_heads
  gitweb: group remote heads by remote
  gitweb: provide a routine to display (sub)sections
  gitweb: refactor repository URL printing
  gitweb: remotes view for a single remote
  gitweb: allow action specialization in page header
  gitweb: nagivation menu for tags, heads and remotes
  gitweb: separate heads and remotes lists
  gitweb: git_get_heads_list accepts an optional list of refs
  gitweb: introduce remote_heads feature
  gitweb: use fullname as hash_base in heads link